1. What is a baby’s 100th birthday photo? A baby\’s 100th birthday photo refers to a special photo taken of a baby, usually when the baby is 100 days old. This kind of photos can record every moment of your baby\’s growth and leave beautiful memories. 2. The significance of a baby’s 100th birthday photo. Everyone hopes that their child will grow up healthily and happily, and taking a baby’s 100th birthday photo can record every stage of the child’s growth, making parents feel warmer when recalling it in the future. In addition, this kind of photo can also be used as a family souvenir to pass down the family history.